/sci/ - Science & Math

/sci/ i'm confused, i'm studying for my Calc 1 test coming up and there's some problems in the chapter we're being tested on that aren't covered in the chapter itself, nor was done in class, nor can I find an answer on. I understand that when you get a 0/0, 1/0, etc type of answer you should try to manipulate the problem with factoring to get the 0 out of the denominator, but I don't know how the hell to factor these simple functions. I can solve limits with the difference quotient just fine, and if this had some algebraic expressions instead of functions, I can do it. But I'm fucking lost on this. The answer is 3, how the hell do you do this? Please help, my teacher is a real dick and I know he's going to throw this shit on there just because it's technically in the book but not specifically covered in detail.